open cylindrical reinforced concrete shell, vibrations, frequency, spectrum, modulus of elasticity.

Thin-walled cylindrical shells made of reinforced concrete are widely used as coatings of buildings and structures. Thin-walled shells can cover large flights and create more closure of the room without additional supports, with optimal shape and good techno-econmic indicators. At present, the design of buildings and structures does not make special calculations for the occurrence of resonance phenomena, absence of design models and insufficient experimental data. At the same time thin-walled shells are very sensitive to external effects (wind and snow loads) causing forced fluctuations, which lead to the destruction of the structure. For example in 2004 tragedy in Transvaal Park in Moscow killed 28 people, more than 100 were injured; in 2010, a roof section collapsed at a stadium in Minnesota, United States, collapsing the podium; in 2015, an accident at the Komsomolsk-on-Amur oil plant under construction caused by fluctuations from wind loads; in 2015, (Top-Irmen of Novosibirsk region) roof of the covered rink failed to withstand joint wind and snow loads; in 2017, the roof of a school in Murino village collapsed; in 2018, the deformation of the roof of the Istra rink under construction was catastrophic. The purpose of theoretical calculations and carrying out excreta with reinforced concrete shells with different modules of elasticity is to ensure reliability during operation of the building and structure, and to avoid accidents, arising resonance phenomena of free oscillations of shells due to external forces (loads).

The article presents the results of experimental studies on determination of spectra, forced and free oscillations of reinforced concrete shell with different modules of elasticity. The whole, carrying out research of reinforced concrete shells is determination of frequencies and form of oscillation of open shells due to external effects. The paper considers the theoretical calculation of the open shell based on the equations of the theory of shallow thin-walled shells, using the Bubnov– Galerkin method, by which we determine how the parameters of the shell affect the processes of free oscillation.

After the studies, the data of the vibration spector dependence on the concrete class are obtained, with the help of these results it can be concluded that as the concrete class increases, the average values of the oscillation frequencies decrease, and the initial values of the oscillation frequencies almost fade.

Sysoev Oleg Evgenyevich,

Doctor of Engineering, Professor, Dean, Komsomolsk-on-Amur of State University, Komsomolsk-on-Amur, Russia.

Qahorov Komiljon Qahorovich,

graduate student, Komsomolsk-on-Amur of State University, Komsomolsk-on-Amur, Russia.

Sysoev Evgeniy Olegovich,

Candidate of Economic Sciences, Associate Professor, Komsomolsk-onAmur of State University, Komsomolsk-on-Amur, Russia.

Zhuravlyova Ekaterina Victorovna,

Undergraduate, Komsomolsk-on-Amur of State University, Komsomolsk-on-Amur, Russia.